Simultaneous biplane single-beat assessment of left ventricular systolic function in patients with atrial fibrillation

Echocardiographic assessment of atrial, ventricular, and valvular function in patients with atrial fibrillation-an expert proposal by the german working group of cardiovascular ultrasound

Echocardiography in patients with atrial fibrillation is challenging due to the varying heart rate. Thus, the topic of this expert proposal focuses on an obvious gap in the current recommendations about diagnosis and treatment of atrial fibrillation (AF)-the peculiarities and difficulties of echocardiographic imaging. The assessment of systolic and diastolic function-especially in combination with valvular heart diseases-by echocardiography can basically be done by averaging the results of echocardiographic measurements of the respective parameters or by the index beat approach, which uses a representative cardiac cycle for measurement. Therefore, a distinction must be made between the functionally relevant status, which is characterized by the averaging method, and the best possible hemodynamic status, which is achieved with the most optimal left ventricular (LV) filling according to the index beat method with longer previous RR intervals. This proposal focuses on left atrial and left ventricular function and deliberately excludes problems of echocardiography when assessing left atrial appendage in terms of its complexity. Echocardiography of the left atrial appendage is therefore reserved for its own expert proposal.

Dynamic Regularized Adaptive Cluster Optimization (DRACO) for Quantitative Cardiac Cine MRI in Complex Arrhythmias

BACKGROUND

Irregular cardiac motion can render conventional segmented cine MRI nondiagnostic. Clustering has been proposed for cardiac motion binning and may be optimized for complex arrhythmias.

PURPOSE

To develop an adaptive cluster optimization method for irregular cardiac motion, and to generate the corresponding time-resolved cine images.

STUDY TYPE

Prospective.

SUBJECTS

Thirteen with atrial fibrillation, four with premature ventricular contractions, and one patient in sinus rhythm.

FIELD STRENGTH/SEQUENCE

Free-running balanced steady state free precession (bSSFP) with sorted golden-step, reference real-time sequence.

ASSESSMENT

Each subject underwent both the sorted golden-step bSSFP and the reference Cartesian real-time imaging. Golden-step bSSFP images were reconstructed using the dynamic regularized adaptive cluster optimization (DRACO) method and k-means clustering. Image quality (4-point Likert scale), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), edge sharpness, and ventricular function were assessed.

STATISTICAL TESTS

Paired t-tests, Friedman test, regression analysis, Fleiss' Kappa, Bland-Altman analysis. Significance level P < 0.05.

RESULTS

The DRACO method had the highest percent of images with scores ≥3 (96% for diastolic frame, 93% for systolic frame, and 93% for multiphase cine) and the percentages were significantly higher compared with both the k-means and real-time methods. Image quality scores, SNR, and CNR were significantly different between DRACO vs. k-means and between DRACO vs. real-time. Cardiac function analysis showed no significant differences between DRACO vs. the reference real-time.

CONCLUSION

DRACO with time-resolved reconstruction generated high quality images and has early promise for quantitative cine cardiac MRI in patients with complex arrhythmias including atrial fibrillation.

LEVEL OF EVIDENCE: 1

TECHNICAL EFFICACY

Stage 2.

Renal function improvement correlates with 3D echocardiographic findings: Effect of surgical mitral valve repair

BACKGROUND

The association between surgical treatment of mitral regurgitation (MR) and renal function is not sufficiently well-known. We tried to evaluate renal function before and after the procedure of surgical mitral valve repair (SMVR) in degenerative severe MR.

METHODS

Patients with primary severe (4+) MR and normal left ventricular ejection fraction (LVEF) that underwent SMVR, examined by a cutting-edge 3-dimensional (3D) echocardiographic probe were enrolled in this study. We took three CKD-EPI equations to measure estimated glomerular filtration rate (eGFR) before SMVR and shortly before patients discharge. A total of 40 patients with baseline lower mean eGFR were evaluated.

RESULTS

Measurements substantiated statistically significant improvements in eGFR (p < 0.001), multivariable linear regression modeling indicating prominent associations between increase in eGFR and decrease of MR (p = 0.003), decline of pulmonary arterial systolic pressure (p = 0.018), as well as increment of forward stroke volume (p = 0.02), in spite of LVEF reduction, left ventricular global longitudinal strain worsening and left atrial ejection fraction impairment.

CONCLUSIONS

Renal function improves after SMVR in patients with degenerative significant MR and preserved LVEF, regardless of cardiac functional worsening.

Improving the diagnosis of heart failure in patients with atrial fibrillation

OBJECTIVE

To improve the echocardiographic assessment of heart failure in patients with atrial fibrillation (AF) by comparing conventional averaging of consecutive beats with an index-beat approach, whereby measurements are taken after two cycles with similar R-R interval.

METHODS

Transthoracic echocardiography was performed using a standardised and blinded protocol in patients enrolled in the RATE-AF (RAte control Therapy Evaluation in permanent Atrial Fibrillation) randomised trial. We compared reproducibility of the index-beat and conventional consecutive-beat methods to calculate left ventricular ejection fraction (LVEF), global longitudinal strain (GLS) and E/e' (mitral E wave max/average diastolic tissue Doppler velocity), and assessed intraoperator/interoperator variability, time efficiency and validity against natriuretic peptides.

RESULTS

160 patients were included, 46% of whom were women, with a median age of 75 years (IQR 69-82) and a median heart rate of 100 beats per minute (IQR 86-112). The index-beat had the lowest within-beat coefficient of variation for LVEF (32%, vs 51% for 5 consecutive beats and 53% for 10 consecutive beats), GLS (26%, vs 43% and 42%) and E/e' (25%, vs 41% and 41%). Intraoperator (n=50) and interoperator (n=18) reproducibility were both superior for index-beats and this method was quicker to perform (p<0.001): 35.4 s to measure E/e' (95% CI 33.1 to 37.8) compared with 44.7 s for 5-beat (95% CI 41.8 to 47.5) and 98.1 s for 10-beat (95% CI 91.7 to 104.4) analyses. Using a single index-beat did not compromise the association of LVEF, GLS or E/e' with natriuretic peptide levels.

CONCLUSIONS

Compared with averaging of multiple beats in patients with AF, the index-beat approach improves reproducibility and saves time without a negative impact on validity, potentially improving the diagnosis and classification of heart failure in patients with AF.

Is echocardiography valid and reproducible in patients with atrial fibrillation? A systematic review

Aims

Echocardiography is vital in the routine assessment and management of atrial fibrillation (AF). We performed a systematic review of the validity and reproducibility of echocardiographic left ventricular systolic and diastolic function in AF, and optimal acquisition methods.

Methods and results

Online databases were searched for studies in patients with AF at the time of echocardiography (1960 to August 2015), prospectively registered with PROSPERO (CRD42015025297). The systematic review included 32 studies from 3 066 search results (1 968 patients with AF). Average age was 67 years, 33% were women, mean LVEF 53% (±10%), and average E/e’ 11.7 (±2.7). Data on the validity and reproducibility of systolic indices were extremely limited. In contrast, diastolic parameters demonstrated correlation with invasive filling pressure and adequate reproducibility: E/e’ (n = 444) r = 0.47 to 0.79; IVRT (n = 177) r = –0.70 to –0.95; E/Vp` (n = 55) r = 0.63 and 0.65; pulmonary vein diastolic flow (n = 67) r = –0.80 and –0.91. Elevated E/e’ (>15) was associated with functional capacity, quality of life, and impaired prognosis. For optimal acquisition in AF patients, cardiac cycles with controlled heart rate (<100 beats/min) and similar preceding and pre-preceding RR intervals are required. Cardiac cycle length and equivalence were more important than the number of beats averaged.

Conclusion

With careful selection of appropriate cardiac cycles, echocardiography is a valid tool to identify diastolic dysfunction in AF, and E/e’ is an independent marker of clinical status and adverse prognosis. However, data on systolic function was extremely limited and requires further prospective study and assessment of variability in clinical practice.

Measuring left ventricular peak longitudinal systolic strain from a single beat in atrial fibrillation: validation of the index beat method

BACKGROUND

It is traditionally difficult to estimate left ventricular (LV) systolic function in atrial fibrillation (AF). The aim of this study was to validate the use of an index beat, the beat after the nearly equal preceding (RR1) and pre-preceding (RR2) intervals, for the measurement of LV peak longitudinal systolic strain (PLSS). The difference between RR1 and RR2 intervals of the index beat must be <60 msec. LV PLSS measured from the index beat (PLSSindex) was compared with LV PLSS measured from the conventional but time-consuming method of averaging multiple cardiac cycles (PLSSavg).

METHODS

Ninety-eight patients with persistent or permanent AF and resting ventricular rates ≤ 105 beats/min were prospectively included. LV PLSSindex and LV PLSSavg were obtained from two-dimensional speckle-tracking echocardiography.

RESULTS

LV PLSSindex had a highly significant correlation with LV PLSSavg (r = 0.970, P < .001). Bland-Altman analysis showed only small bias of 0.01%, and the 95% limits of agreement were +1.64% to -1.62%. Compared with those with lower risk scores of stroke indicated by CHADS(2) scores < 2 or CHA(2)DS(2)-VASc scores < 2, patients with higher risk scores of stroke indicated by CHADS(2) scores ≥ 2 or CHA(2)DS(2)-VASc scores ≥ 2 had lower PLSSavg and PLSSindex (P ≤ .012).

CONCLUSIONS

LV PLSSindex was a good alternative to LV PLSSavg in patients with AF. Use of the index beat to measure LV longitudinal systolic strain in patients with AF was as accurate as the time-consuming method of averaging multiple cardiac cycles.

Diagnostic accuracy of NT-proBNP ratio (BNP-R) for early diagnosis of tachycardia-mediated cardiomyopathy: a pilot study

BACKGROUND

When heart failure and tachycardia occur simultaneously, a useful diagnostic tool for early discrimination of patients with benign tachycardia-mediated cardiomyopathy (TMC) versus major structural heart disease (MSHD) is not available. Such a tool is required to prevent unnecessary and wearing diagnostics in patients with reversible TMC. Moreover, it could lead to early additional diagnostics and therapeutic approaches in patients with MSHD.

METHODS

A total of 387 consecutive patients with supraventricular arrhythmia underwent assessment at a single center. Of these patients, 40 fulfilled the inclusion criteria with a resting heart rate ≥100 bpm and an impaired left ventricular ejection fraction <40%. In all patients, successful electrical cardioversion was performed. At baseline, day 1 and weekly for 4 weeks, levels of NT-proBNP and echocardiographic parameters were evaluated. An NT-proBNP ratio (BNP-R) was calculated as a quotient of baseline NT-proBNP/follow-up NT-proBNP. After 4 weeks, cardiac catheterization was performed to identify patients with a final diagnosis of TMC versus MSHD.

RESULTS

Initial NT-proBNP concentrations were elevated and consecutively decreased after cardioversion in all patients. Multivariate regression and ROC analysis revealed that BNP-R discriminated between patients with TMC versus MSHD independent and superior to all other variables. The area under the ROC curve for BNP-R to detect TMC was 0.90 (95% CI 0.79-1.00; p < 0.001) after 1 week and 0.995 (95% CI 0.99-1.00; p < 0.0001) after 4 weeks. One week after cardioversion already, a BNP-R cutoff ≥2.3 was useful for TMC diagnosis indicated by an accuracy of 90%, sensitivity of 84% and specificity of 95%.

CONCLUSION

BNP-R was found to be highly accurate for the early diagnosis of TMC.

Refinement on single-beat determination of left ventricular systolic function in patients with atrial fibrillation

Single-beat determination of left ventricular systolic function at a beat with equal subsequent cardiac cycles has been proposed as an accurate method in atrial fibrillation. However, there has still been substantial variability between the values calculated from beats with equal subsequent cycles. Therefore, some refinement on the single-beat method is needed. In 100 patients with atrial fibrillation, Doppler aortic flow time-velocity integral was determined for at least 20 consecutive cardiac cycles. The values at beats with equal subsequent cardiac cycles were chosen and compared with the average values over all cardiac cycles. The values at beats with cycle lengths shorter than 500 milliseconds were usually far below the average values over all cardiac cycles. Bland-Altman agreement analysis revealed improved accuracy by gradually narrowing the range of the limits of agreement when 2 or 3 beats with equal subsequent cycles and cycle lengths longer than 500 milliseconds were used for evaluation.

Biplane assessment of left ventricular function during atrial fibrillation at beats with equal subsequent cycles

BACKGROUND

Prior study has demonstrated that the biplane single-beat method could be used to assess left ventricular function during atrial fibrillation at a beat with equal subsequent cycles. The study was to test whether we could improve the method by measuring a few beats with equal subsequent cycles and cycle-length limits.

METHODS

In 75 patients with atrial fibrillation, stroke volume and ejection fraction were determined from simultaneous biplane views of left ventricle for 20 beats using a matrix-array transducer and a biplane Simpson's rule. The influence of cycle lengths on the values of systolic parameters at beats with equal subsequent cycles was examined from the plot of normalized parameters (measured values/average values) against cycle lengths. The values of 1 to 3 beats with equal subsequent cycles and cycle-length limits were averaged and compared with the average values over 20 beats by Bland-Altman and mean percentage difference analysis. The variability of repeat measurements was evaluated in 10 patients.

RESULTS

The systolic parameters measured at beats with cycle lengths shorter than 500 ms were usually far below the average values. Agreement and mean percentage difference analysis revealed improved accuracy when 2 or 3 beats with cycle-length limits (>500 ms) were used for assessment. As the variability of averaging 2 or 3 beats is no greater than that of repeat measurements, both methods are equally good.

CONCLUSIONS

Accurate assessment of left ventricular systolic function in atrial fibrillation can be obtained by averaging 2 beats with equal subsequent cycles and cycle-length limits (>500 ms).